This disclosure relates to a method for determining the position of an underground magnetic source.
A need often exists when drilling a borehole to determine the existence and position of an underground magnetic source, such as drill string or casing (hereinafter “existing underground piping”). For instance, when drilling a relief well or otherwise attempting an intercept of an existing underground piping, knowledge of the precise position of the existing underground piping may be not be available. Similarly, drilling in a crowded underground space, such as in field with earlier-drilled wellbores or multiple wells from a single pad or closely located pad, may present challenges in avoiding underground piping. Previous surveys of the existing underground piping may be unavailable or inaccurate.
Existing underground piping has a magnetic field that may be detected (hereinafter an “underground magnetic source.” Determining the position and size of the underground magnetic source may not always be possible with existing equipment and techniques.